4L 5s refers to the structure of MOS Scales whose generator falls between 2\9 (two degrees of 9edo = approx. 266.667¢) and 1\4 (one degree of 4edo = 300¢). In the case of 9edo, L and s are the same size; in the case of 4edo, s is so small it disappears. The spectrum, then, goes something like:
Generator
Scale
Generator in cents
Comments
2\9
1 1 1 1 1 1 1 1 1
266.667
9\40
4 5 4 5 4 5 4 5 4
270
7\31
3 4 3 4 3 4 3 4 3
270.968
12\53
5 7 5 7 5 7 5 7 5
271.698
Orwell is around here
5\22
2 3 2 3 2 3 2 3 2
272.727
Optimum rank range (L/s=3/2) orwell
2 pi 2 pi 2 pi 2 pi 2
273.412
13\57
5 8 5 8 5 8 5 8 5
273.684
Golden orwell (bad tuning)
8\35
3 5 3 5 3 5 3 5 3
274.286
1 √3 1 √3 1 √3 1 √3 1
274.85
11\48
4 7 4 7 4 7 4 7 4
275
3\13
1 2 1 2 1 2 1 2 1
276.923
Boundary of propriety:
generators smaller than this are proper
10\43
3 7 3 7 3 7 3 7 3
279.07
7\30
2 5 2 5 2 5 2 5 2
280.000
11\47
3 8 3 8 3 8 3 8 3
280.851
1 e 1 e 1 e 1 e 1
281.100
L/s = e
4\17
1 3 1 3 1 3 1 3 1
282.353
L/s = 3
1 pi 1 pi 1 pi 1 pi 1
282.922
L/s = pi
9\38
2 7 2 7 2 7 2 7 2
284.2105
5\21
1 4 1 4 1 4 1 4 1
285.714
L/s = 4
6\25
1 5 1 5 1 5 1 5 1
288
1\4
0 1 0 1 0 1 0 1 0
300.000
Note that between 7\31 and 5\22, g approximates frequency ratio 7:6, 2g approximates 11:8, and 3g approximates 8:5. This defines the range of Orwell Temperament, which is the only notable harmonic entropy minimum with this MOS pattern. 4L 5s scales outside of that range are not suitable for Orwell.
generators smaller than this are proper
Note that between 7\31 and 5\22, g approximates frequency ratio 7:6, 2g approximates 11:8, and 3g approximates 8:5. This defines the range of Orwell Temperament, which is the only notable harmonic entropy minimum with this MOS pattern. 4L 5s scales outside of that range are not suitable for Orwell.